It is well known that contact lenses can be used to improve vision. Various contact lenses have been commercially produced for many years. Hydrogel contact lenses are formed from hydrophilic polymers and copolymers containing repeating units such as 2-hydroxyethyl methylacrylate (HEMA). Of these, contact lenses formed from copolymers of HEMA and methacrylic acid, are among the most comfortable, and have the lowest rate of adverse events. Contact lenses formed from copolymers of HEMA and MAA, such ACUVUE®2 brand contact lenses, display substantial amounts of lysozyme uptake (greater than 500 μg) and retain a majority of the uptaken proteins in their native state. However, hydrogel contact lenses generally have oxygen permeabilities that are less than about 30.
Contact lenses made from silicone hydrogels have been disclosed. These silicone hydrogel lenses have oxygen permeabilities greater than about 60, and many provide reduced levels of hypoxia compared to conventional hydrogel contact lenses. Silicone hydrogel lenses may be exposed to extended periods of wear such as for several days in a row, for example, up to about 30 days.
U.S. Pat. No. 8,815,972 (Rathore) is directed to ionic silicone hydrogels having improved hydrolytic stability and desirable protein uptake.
U.S. Pat. No. 7,786,185 is directed to wettable hydrogels comprising acyclic polyamides.